Question

我的应用程序中有一个RSS提要，我正在试图找出如何实现提取刷新。这是我的代码：

#import "ActionAlertsViewController.h"
#import "RSSChannel.h"
#import "RSSItem.h"
#import "WebViewController.h"
#import "DTCustomColoredAccessory.h"
#import "SVProgressHUD.h"

@implementation ActionAlertsViewController
{
    UIActivityIndicatorView *loadingIndicator;
}
@synthesize webViewController;

- (void)viewDidLoad
{
    UIImageView *background = [[UIImageView alloc]init];
    background.image = [UIImage imageNamed:@"plain_app-background.png"];

    self.tableView = [[UITableView alloc] initWithFrame:CGRectZero style:UITableViewStyleGrouped];
    [self.tableView setBackgroundView:background];
    self.title = @"Action Alerts";

    [[SVProgressHUD appearance]setHudBackgroundColor:[UIColor blackColor]];
    [[SVProgressHUD appearance]setHudForegroundColor:[UIColor whiteColor]];

    [SVProgressHUD showWithStatus:@"Loading"];
}

- (void)viewDidDisappear:(BOOL)animated
{
    [SVProgressHUD dismiss];
}

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
    NSLog(@"%@ found a %@ element", self, elementName);
    if ([elementName isEqual:@"channel"])
    {
        // If the parser saw a channel, create new instance, store in our ivar
        channel = [[RSSChannel alloc]init];

        // Give the channel object a pointer back to ourselves for later
        [channel setParentParserDelegate:self];

        // Set the parser's delegate to the channel object
        [parser setDelegate:channel];
    }
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // return 0;
    NSLog(@"channel items %d", [[channel items]count]);
    return [[channel items]count];
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return 50;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    // return nil;

    UIImageView *image = [[UIImageView alloc]init];
    image.image = [UIImage imageNamed:@"CellImage.png"];

    UIImageView *background = [[UIImageView alloc]init];
    background.image = [UIImage imageNamed:@"plain_app-background.png"];

    UIImageView *highlightedCellImage = [[UIImageView alloc]init];
    highlightedCellImage.image = [UIImage imageNamed:@"HighlightedCellImage"];

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"UITableViewCell"];
    if (cell == nil)
    {
        cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"UITableViewCell"];
        cell.textLabel.font=[UIFont systemFontOfSize:16.0];
    }
    RSSItem *item = [[channel items]objectAtIndex:[indexPath row]];
    NSDateFormatter *formatter = [[NSDateFormatter alloc]init];
    [formatter setDateFormat:@"EEE, dd MMM yyyy HH:mm:ssZ"];
    NSDate *pubDate = [formatter dateFromString:[item date]];
    [formatter setDateStyle:NSDateFormatterMediumStyle];
    NSString *dateString = [formatter stringFromDate:pubDate];
    NSLog(@"Date String: %@", dateString);

    [[cell textLabel]setText:[item title]];
    [[cell detailTextLabel]setText:dateString];

    NSLog(@"Date: %@", [item date]);

    tableView.backgroundColor = [UIColor clearColor];
    cell.textLabel.backgroundColor = [UIColor clearColor];
    cell.textLabel.highlightedTextColor = [UIColor blueColor];
    cell.textLabel.font = [UIFont fontWithName:@"FranklinGothicStd-ExtraCond" size:20.0];
    cell.textLabel.textColor = [UIColor whiteColor];
    cell.detailTextLabel.backgroundColor = [UIColor clearColor];
    cell.detailTextLabel.highlightedTextColor = [UIColor blueColor];
    cell.detailTextLabel.font = [UIFont fontWithName:@"FranklinGothicStd-ExtraCond" size:14.0];
    cell.detailTextLabel.textColor = [UIColor whiteColor];
    cell.backgroundView = image;
    cell.selectedBackgroundView = highlightedCellImage;
    tableView.backgroundView = background;

    DTCustomColoredAccessory *accessory = [DTCustomColoredAccessory accessoryWithColor:cell.textLabel.textColor];
    accessory.highlightedColor = [UIColor blueColor];
    cell.accessoryView =accessory;

    return cell;
}

- (void)fetchEntries
{
    // Create a new data container for the stuff that comes back from the service
    xmlData = [[NSMutableData alloc]init];

    // Construct a URL that will ask the service for what you want
    NSURL *url = [NSURL URLWithString:@"http://kyfbnewsroom.com/category/public-affairs/notifications/feed/"];

    // Put that URL into an NSURLRequest
    NSURLRequest *req = [NSURLRequest requestWithURL:url];

    // Create a connection that will exchange this request for data from the URL
    connection = [[NSURLConnection alloc]initWithRequest:req delegate:self startImmediately:YES];
}

- (id)initWithStyle:(UITableViewStyle)style
{
    self = [super initWithStyle:style];

    if (self)
    {
        [self fetchEntries];
    }

    return self;
}

// This method will be called several times as the data arrives
- (void)connection:(NSURLConnection *)conn didReceiveData:(NSData *)data
{
    // Add the incoming chunk of data to the container we are keeping
    // The data always comes in the correct order
    [xmlData appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)conn
{
    /* We are just checking to make sure we are getting the XML
     NSString *xmlCheck = [[NSString alloc]initWithData:xmlData encoding:NSUTF8StringEncoding];
     NSLog(@"xmlCheck = %@", xmlCheck);*/

    [SVProgressHUD dismiss];

    // Create the parser object with the data received from the web service
    NSXMLParser *parser = [[NSXMLParser alloc]initWithData:xmlData];

    [parser setDelegate:self];

    [parser parse];

    // Get rid of the XML data as we no longer need it
    xmlData = nil;

    // Reload the table.. for now, the table will be empty
    NSMutableArray *notActionAlerts = [NSMutableArray array];
    for (RSSItem *object in channel.items) {
        if (!object.isActionAlert) {
            [notActionAlerts addObject:object];
        }
    }

    for (RSSItem *object in notActionAlerts) {
        [channel.items removeObject:object];
    }

    [[self tableView]reloadData];

    NSLog(@"%@\n %@\n %@\n", channel, [channel title], [channel infoString]);
}

- (void)connection:(NSURLConnection *)conn didFailWithError:(NSError *)error
{
    // Release the connection object, we're done with it
    connection = nil;

    // Release the xmlData object, we're done with it
    xmlData = nil;

    [SVProgressHUD dismiss];

    // Grab the description of the error object passed to us
    NSString *errorString = [NSString stringWithFormat:@"Fetch failed: %@", [error localizedDescription]];

    // Create and show an alert view with this error displayed
    UIAlertView *av = [[UIAlertView alloc]initWithTitle:@"Error" message:errorString delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [av show];
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    [[webViewController webView]loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"about:blank"]]];

    // Push the web view controller onto the navigation stack - this implicitly creates the web view controller's view the first time through
    // [[self navigationController]pushViewController:webViewController animated:YES];
    [self.navigationController pushViewController:webViewController animated:YES];

    // Grab the selected item
    RSSItem *entry = [[channel items]objectAtIndex:[indexPath row]];

    // Construct a URL with the link string of the item
    NSURL *url = [NSURL URLWithString:[entry link]];

    // Construct a request object with that URL
    NSURLRequest *req = [NSURLRequest requestWithURL:url];

    // Load the request into the web view
    [[webViewController webView]loadRequest:req];
    webViewController.hackyURL = url;
    // Set the title of the web view controller's navigation item
    // [[webViewController navigationItem]setTitle:[entry title]];
}

@end

Answer 1

如果您正在使用故事板，那么您可以原生支持pull-to-refresh。

enter image description here

只需将Refreshing更改为enabled，然后您就可以为此活动挂钩。

为RSS Feed实施Pull to Refresh

1 个答案: